It looks like my venerable G4 Powerbook is dead...

Okay, well not wholly deceased, but the screen is looking like a legion of red ants are lining up for a mass picnic invasion, and the HD is starting to get tired. For the red ants, should I diagnose this as a video card issue, and if so, how much to replace/fix? I know the card is soldered onto the motherboard, so it's got to be on the high $$$ side for a brand new one. Would it be so high that I should just consider a MBP upgrade?